In recent years, a number of platinum(II) complexes, including well-known cisplatin, have been synthesized and have been reported to have antitumor activity. We, the present inventors, have synthesized some platinum(II) complexes, as disclosed, for example, in Japanese Patent Application First Publn. (KOKAI) Nos. 31648/78. 35013/80, 130992/80, 103192/81, 156416/82, 16895/82, 21697/84, 34982/85, 34983/85, 97991/85, 109521/85 and 59289/87; Japanese Patent Application Second Publn. (KOKOKU) Nos. 29957/83, 34958/85 and 41077/85 as well as U.S. Pat. Nos. 4,169,846; 4,200,583; 4,256,652; 4,255,347; 4,551,524 and U.S. patent appln. Ser. No. 637,463 and European Patent Nos. 1126 and 8936, European Patent Appln. Nos. 83 303659.3 and 84 305304.2.
We have also synthesized some organoplatinum(IV) complexes, as disclosed, for example, in Japanese Patent Application First Publication (KOKAI) Nos. 87295/85 and 109521/85; Japanese Patent Appln. No. 48625/86, as well as U.S. patent appln. Ser. No. 020,893 and European Patent Appln. No. 87 420061.1.
Although a variety of platinum complexes as above has been known to date, there is still a standing demand for a novel compound having more excellent antitumor activities. It is a primary object of this invention to provide such a novel antitumor platinum compound.